There is a great deal of confusion between Oregano (f283) and Marjoram, partly because of their similar appearance, including the square stems, opposing pairs of leaves and whorled flower spikes typical of the Lamiaceae or Mint family.

Moreover, the plants are very closely related, and classification that differed in the past still causes confusion. Now the genus name for both plants is Origanum, and Marjorams are considered types of Oregano, of which there are over 50. Sweet Marjoram (Origanum majorana) is the most familiar Marjoram. But this official clarity does not prevent another type of Marjoram, Pot Marjoram (Origanum onites), from Crete, from being called Cretan Oregano. Even plants outside the genus are marketed as Oregano: Coleus anboinicus in Puerto Rico (part of traditional Cuban seasoning), Thymus nummularius in Spain, and Lippia graveolens in Mexico. Conversely, Origanum vulgare, or Common Oregano, may be called Wild Marjoram.

HerbA herb, which may result in allergy symptoms in sensitised individuals.

Allergen Exposure

Geographical distributionThe sub-bushy plant Marjoram originated in the southern Mediterranean region and spread to southern Europe very early. For the Greeks, it was sacred, made into wreaths for weddings and funerals.

Marjoram is a member of the Lamiaceae or Mint family, which includes many familiar culinary herbs: Mint, Basil, Oregano and Sage. Although Marjoram and Oregano (see Oregano Rf283) are similar in appearance (see above), Sweet Marjoram is more compact and typically grows in a “mound”, with branches spilling over and taking root where they touch the ground, whereas many kinds of Oregano are upright. Marjoram flowers tend to be white, and the leaves smaller (only up to 2.5 cm) and grayish-green and softer-textured. They have a distinctive fragrance and taste (but less strong than those of Oregano), which give them broad culinary uses. Marjoram is rather delicate and is classified as a summer annual in most regions, in contrast to Oreganos in general, which are held to be perennials.

EnvironmentMarjoram is most often used in recipes of French or English origin, whereas Oregano's more robust flavour is habitually called for in Italian, Greek, North African and Mexican cuisines. Marjoram is far from unknown in Mediterranean cooking, however. It is not strongly associated with particular dishes; rather, it is a familiar ingredient of many soups and stews, and often flavours poultry and seafood. It frequently features in blends of herbs, and can be made into a tea.

The essential oil comprises between 0.7% and 3.5%. The main aroma component is a bicyclic monoterpene alcohol, cis-sabinene hydrate. Oil of Marjoram is used in perfumes. Medicinal uses include pain relief and the treatment of digestive complaints.

Unexpected exposureSee under Environment.

AllergensNo allergens from this plant have yet been characterised.

Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, and in particular between Oregano and Marjoram (1).

Clinical Experience

IgE-mediated reactionsMarjoram may uncommonly induce symptoms of food allergy in sensitised individuals. As little has been reported in the literature, adverse reactions to the closely related family member Oregano will be of help.

A 45-year-old man experienced 3 reactions to food: as a result of Oregano on a single occasion, and twice to Thyme. He had pruritis and swelling of the lips and tongue, dysphagia, dysphonia, and progressive upper respiratory difficulty, as well as intense facial and palpebral oedema. On 2 occasions he also had hypotension, vomiting, and nausea. Onset was within minutes after the ingestion of pizza containing the herb in the first instance, meat seasoned with Thyme in the second, and snails with Thyme in the third (2).

A 45-year-old female patient, with facial eczema that appeared 20 minutes after ingestion of Oregano and was exacerbated by sun exposure, was reported. A patch test was positive. Three other patients were reported to be positive to Oregano on a patch test, but their symptoms were not described (3).

Perioral dermatitis following ingestion of Marjoram has been reported (4).